The present invention relates to a cutting apparatus, and more particularly to a cutting apparatus designed for use in horticulture.
As shown in FIG. 1, the structure of a conventional cutting apparatus for use in horticulture comprises a first cutting device 10 and a second cutting device 14. The first cutting device 10 is of a long batten-like construction with toothed cutting parts 11 disposed across both lateral edges thereof and with a plurality of holes 12 arranged lengthwise at the positions coinciding with the axial line thereof. The end portion 13 of the first cutting device 10 is used to hinge thereto an actuator (not shown in FIG. 1). The second cutting device 14 is of a long batten-like construction and is arranged over the first cutting device 10. The second cutting device 14 has toothed cutting parts 15 disposed across both lateral edges thereof and has the first elongated hole 16 arranged at the position coinciding with the axial line thereof and corresponding to the hole 12 of the first cutting device 10. The end portion 17 of the second cutting device 14 is used to hinged thereto the driveshaft of an actuator. A retaining plate 18 of a U-shaped construction in its cross-section, which is placed over the second cutting device 14, has a plurality of holes 19 disposed therein at the positions corresponding to holes 12 of the first cutting device 10. The first and the second cutting devices 10 and 14 and the retaining plate 18 are held together by means of a plurality of bolts 20 and nuts 21. A sleeve 22 of a predetermined height is lodged in the first elongated hole 16 in order to maintain an appropriate gap between the retaining plate 18 and the first cutting device 10 so that there is a sufficient room for the second cutting device 14 to move axially in a reciprocating manner. As a result of the fact that the bolt 20 traverses the sleeve 22, the second cutting device 14 is capable of moving between the first cutting device 10 and the retaining plate 18 for a certain distance corresponding to the length of the elongated hole 16 upon an activation of the actuator, which will not be expounded here because it is a subject beyond the scope of this invention. Consequently, the cutting effect is brought about by the movement of the cutting parts 11 and 15 in an alternate manner.
The conventional cutting apparatus of prior art described above has inherent deficiencies of its own. In order to ensure that the first and the second cutting devices 10 and 14 move in a linear manner without deviation, the outer diameter of the sleeve 22 must be appropriately corresponding to the width of the elongated hole 16; otherwise a deviation of the prescribed course of movement of second cutting device 14 will take place, resulting in a servere mechanical friction between the sleeve 22 and the inner wall of the elongated hole 16. As a result, an undesirable noize is generated when the cutting apparatus of prior art is at work. In addition, the cutting effect of the apparatus is greatly compromised by virtue of a mechanical friction between the sleeve 22 and the elongated hole 16.
The first and the second cutting devices 10 and 14 of the prior art cutting apparatus are generally made of the heat-treated metals, which are vulnerable to bending and deformation. As a result, the first and the second cutting devices 10 and 14 are so often assembled improperly that there are unwanted gaps formed therebetween so as to permit the debris of the twig and the grass to deposit thereinto.